<template>
  <div class="article-container">
    <!-- 导航栏 -->
    <van-nav-bar
      class="page-nav-bar"
      left-arrow
      @click-left="$router.back()"
      title="黑马头条"
    ></van-nav-bar>
    <!-- /导航栏 -->

    <div
      ref="main_wrap"
      class="main-wrap"
    >
      <!-- 加载中 -->
      <div
        class="loading-wrap"
        v-if="isLoading"
      >
        <van-loading
          color="#3296fa"
          vertical
        >加载中</van-loading>
      </div>
      <!-- /加载中 -->

      <!-- 加载完成-文章详情 -->
      <div
        class="article-detail"
        v-else-if="article.title"
      >
        <!-- 文章标题 -->
        <h1 class="article-title">{{article.title}}</h1>
        <!-- /文章标题 -->

        <!-- 用户信息 -->
        <van-cell
          class="user-info"
          center
          :border="false"
        >
          <van-image
            class="avatar"
            slot="icon"
            round
            fit="cover"
            :src="article.aut_photo"
          />
          <div
            slot="title"
            class="user-name"
          >{{article.aut_name}}</div>
          <div
            slot="label"
            class="publish-date"
          >{{article.pubdate | relativeTime}}</div>
          <Follow
            :isFollowed.sync="article.is_followed"
            :autId="article.aut_id"
          ></Follow>
        </van-cell>
        <!-- /用户信息 -->

        <!-- 文章内容 -->
        <div
          ref="articleContent"
          class="article-content markdown-body"
          v-html="article.content"
        ></div>
        <van-divider>正文结束</van-divider>

        <ArticleList
          @onload-success="totalCount = $event"
          :source="article.art_id"
          :list="commentList"
          @reply-click="onReplyClick"
        ></ArticleList>
        <!-- 底部区域 -->
        <div class="article-bottom">
          <van-button
            class="comment-btn"
            type="default"
            round
            size="small"
            @click="isPostShow = true"
          >写评论</van-button>
          <van-icon
            name="comment-o"
            :badge="totalCount"
            color="#777"
            @click="commentsSection"
          />
          <Collect
            v-model="article.is_collected"
            :artId="article.art_id"
          />
          <Liked
            v-model="article.attitude"
            :artId="article.art_id"
          />
          <van-icon
            name="share"
            color="#777777"
          ></van-icon>
        </div>

        <!-- 发表评论 -->
        <van-popup
          v-model="isPostShow"
          position="bottom"
        >
          <comment-post
            :target="article.art_id"
            @post-success="onPostSuccess"
          />
        </van-popup>

        <!-- 评论回复 -->
        <!--
      弹出层是懒渲染的：只有在第一次展示的时候才会渲染里面的内容，之后它的关闭和显示都是在切换内容的显示和隐藏
     -->
        <van-popup
          v-model="isReplyShow"
          position="bottom"
          style="height: 85%;"
        >
          <!--
        v-if 条件渲染
          true：渲染元素节点
          false：不渲染
       -->
          <comment-reply
            v-if="isReplyShow"
            :comment="currentComment"
            @close="isReplyShow = false"
            @reply-click="onReplyClick"
          />
        </van-popup>
        <!-- /评论回复 -->

        <!-- /底部区域 -->
      </div>
      <!-- /加载完成-文章详情 -->

      <!-- 加载失败：404 -->
      <div
        class="error-wrap"
        v-else-if="errLoading === 404"
      >
        <van-icon name="failure" />
        <p class="text">该资源不存在或已删除！</p>
      </div>
      <!-- /加载失败：404 -->

      <!-- 加载失败：其它未知错误（例如网络原因或服务端异常） -->
      <div
        class="error-wrap"
        v-else
      >
        <van-icon name="failure" />
        <p class="text">内容加载失败！</p>
        <van-button
          class="retry-btn"
          @click="loadArticle"
        >点击重试</van-button>
      </div>
      <!-- /加载失败：其它未知错误（例如网络原因或服务端异常） -->
    </div>
  </div>
</template>

<script>
import { ImagePreview } from 'vant'
import { getArtById } from '@/api/article'
import Follow from '@/components/followed'
import Collect from '@/components/collect'
import Liked from '@/components/liked'
import ArticleList from './components/article-list'
import CommentPost from './components/comment-post'
import CommentReply from '@/views/article/components/comment-reply'
export default {
  name: 'ArticleIndex',
  components: {
    Follow,
    Collect,
    Liked,
    ArticleList,
    CommentPost,
    CommentReply
  },
  provide: function () {
    return {
      articleId: this.articleId
    }
  },
  props: {
    articleId: {
      type: [Number, String, Object],
      required: true
    }
  },
  data () {
    return {
      article: {},
      isLoading: true,
      errLoading: null,
      totalCount: null, // 评论数量
      isPostShow: false, // 发表评论弹出层
      commentList: [], // 评论列表
      isReplyShow: false, // 评论回复弹出层
      currentComment: {} // 点击回复的评论信息
    }
  },
  computed: {},
  watch: {},
  created () {
    this.loadArticle()
  },
  mounted () { },
  methods: {
    async loadArticle () {
      this.isLoading = true
      try {
        // if (Math.random() > 0.5) {
        //   JSON.parse('asdasd')
        // }
        const { data } = await getArtById(this.articleId)
        this.article = data.data
        // console.log(this.article)

        this.isLoading = false
        this.$nextTick(() => { this.imgPreview() })
      } catch (err) {
        if (err.response && err.response.status === 404) {
          this.errLoading = 404
        }
        console.log(err)
      }
      this.isLoading = false
    },
    imgPreview () {
      const articleContent = this.$refs.articleContent
      const imgs = articleContent.querySelectorAll('img')
      const imgUrls = []
      imgs.forEach((obj, index) => {
        imgUrls.push(obj.src)
        obj.onclick = function () {
          ImagePreview({
            images: imgUrls,
            startPosition: index
          })
        }
      })
    },
    onPostSuccess (obj) {
      this.isPostShow = false
      // console.log(obj)
      this.commentList.unshift(obj)
      this.totalCount++
    },
    onReplyClick (comment) {
      this.isReplyShow = false
      this.$nextTick(() => { this.isReplyShow = true })
      this.currentComment = comment
    },
    commentsSection () {
      const scroll = document.querySelector('.article-comments').offsetTop
      // console.log(scroll)
      // this.$refs.main_wrap.scroll(0, scroll)
      // this.$refs.main_wrap.scrollTop = scroll
      this.animation(this.$refs.main_wrap, scroll)
    },
    animation (obj, target) {
      clearInterval(obj.timer)
      obj.timer = setInterval(() => {
        const step = (target - obj.scrollTop) / 10
        const newStep = step > 0 ? Math.ceil(step) : Math.floor(step)
        if (Math.floor(obj.scrollTop) === target || obj.scrollHeight === Math.floor(obj.scrollTop) + obj.clientHeight) {
          clearInterval(obj.timer)
        }
        obj.scrollTop = obj.scrollTop + newStep
      }, 10)
    }
  }
}
</script>

<style scoped lang="less">
@import "./github-markdown.css";
.article-container {
  /deep/ .page-nav-bar {
    background-color: #3296fa;
    .van-nav-bar__title {
      color: #fff;
    }
    .van-icon-arrow-left {
      color: #fff;
    }
  }
  .main-wrap {
    position: fixed;
    left: 0;
    right: 0;
    top: 92px;
    bottom: 88px;
    overflow-y: scroll;
    background-color: #fff;
  }
  .article-detail {
    .article-title {
      font-size: 40px;
      padding: 50px 32px;
      margin: 0;
      color: #3a3a3a;
    }

    .user-info {
      padding: 0 32px;
      .avatar {
        width: 70px;
        height: 70px;
        margin-right: 17px;
      }
      .van-cell__label {
        margin-top: 0;
      }
      .user-name {
        font-size: 24px;
        color: #3a3a3a;
      }
      .publish-date {
        font-size: 23px;
        color: #b7b7b7;
      }
      .follow-btn {
        width: 170px;
        height: 58px;
      }
    }

    .article-content {
      padding: 55px 32px;
      /deep/ p {
        text-align: justify;
      }
    }
  }

  .loading-wrap {
    padding: 200px 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #fff;
  }

  .error-wrap {
    padding: 200px 32px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    background-color: #fff;
    .van-icon {
      font-size: 122px;
      color: #b4b4b4;
    }
    .text {
      font-size: 30px;
      color: #666666;
      margin: 33px 0 46px;
    }
    .retry-btn {
      width: 280px;
      height: 70px;
      line-height: 70px;
      border: 1px solid #c3c3c3;
      font-size: 30px;
      color: #666666;
    }
  }

  .article-bottom {
    position: fixed;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    justify-content: space-around;
    align-items: center;
    box-sizing: border-box;
    height: 88px;
    border-top: 1px solid #d8d8d8;
    background-color: #fff;
    .comment-btn {
      width: 282px;
      height: 46px;
      border: 2px solid #eeeeee;
      font-size: 30px;
      line-height: 46px;
      color: #a7a7a7;
    }
    .van-icon {
      font-size: 40px;
      .van-info {
        font-size: 16px;
        background-color: #e22829;
      }
    }
  }
}
</style>
